Agricultural chemicals and fertilizers must be applied within very narrow time windows for maximum effectiveness. In some cases, this means that application must be performed after the crops have emerged, and sometimes even after the crops have grown to a height of several feet tall. To apply chemicals and fertilizers without damaging standing crops specialized self-propelled agricultural product applicators, having high ground clearance, such as so-called high-boy sprayers or dry product applicators, are often utilized with standing crops. The high ground clearance allows the applicator to move through the standing crops without damaging them.
Such high ground clearance applicators also typically utilize independent drive and suspension systems for each wheel of the applicator, and provide sonic means for adjusting the track width of the wheels to match the row spacing of the crop being treated. Since the row spacing varies for different types of crops, and as a matter of custom in various locations, such self-propelled applicators also typically include some apparatus for adjusting the track width to match the row spacing.
Track-width adjustments systems can be manually operable, but for ease of operation it is more typical to include a powered arrangement for adjusting track width, through use of some form of actuator, such as a hydraulic cylinder, for extending and retracting one or more axles of the applicator in a direction transverse to the direction of travel of the applicator. It is desirable to provide some form of extension limiting arrangement to stop and hold the extendable portion of the axle at a maximum permissible extended position if the track-width adjusting actuator should inadvertently become fully or partly disconnected from the axle. Prior arrangements for limiting axle extension have worked satisfactorily, but are more complex, cumbersome and costly than is desirable. Accordingly, it is desirable to provide an improved telescoping axle arrangement, that includes an improved apparatus and method for limiting axle extension.